Air blast circuit breaker and control therefor



zz zzz 121 AIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR Filed Dec. 21,1940 7 Sheets-Sheet l 1N VEN TOR. We! m M ATTORNEY.

Dec. 11, 1945. w. M. SCOTT, JR 2,390,966

AIR BLAST CIRCUIYi BREAKER AND CONTROL THEREFOR Filed Dec. 21, 1940 7Sheets -Sheet 2 Dec. 11, 1945. w. M. scorT. JR

AIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR Filed Dec. 21, 1940 7Sheets-Sheet a INVENTOR.

ATTORNEY Dc. 11, 1945. I w. M. SCOTT, JR 90,

AIR BLAST CIRCUIT BREAKER AND CC JNTROL THEREFOR 1 Filed Dec. 21, 1940 7Sheets-Sheet 4 INVENTOR.

. u ea. m 4 BY j,

ATTORNEY.

Dec. 11, 1945. w. M. SCOTT, JR 2,390,966

AIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR Filed Dec. 21, 1940 7Sheets-Sheet 5 ATTORNEY.

Dec. 11, 1945. w. M.,SCOTT, JR

AIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR '7 Sheets-Sheet e FiledDec. 21, 1940 ATTORNEY.

Dec. 11, 1945. w. M. SCOTT, JR 2,390,966

AIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR Filed Dec. 21, 1940 ATTORN E Y.

7 Sheets-Sheet 7 Patented Dec. 11, 1945 UNI'TED STATES. PATENT OFFICEAIR BLAST CIRCUIT BREAKER AND CONTROL THEREFOR William M. Scott, Jr.,Bryn Mawr,IPa., assignor to I. '1. E. Circuit Breaker Company,Philadelphia, Pa., a corporation of Pennsylvania 11 Claims.

My invention relates in general to'the' field of circuit interruptersand more specifically concerns a circuit breaker and a control circuittherefor, particularly adaptable to the protection of miizgury arerectifiers and their associated circu The high speed circuit breakerwhich I have devised comprises a pair of cooperable contacts upon whicha directed high velocity air blast may operate to cause contactdisengagement and are extinction with a minimum of time delay.

A diaphragm valve in each of the anode circuit breakers is the air blastcontrol element and all of these valves are interlocked by means of amanifold in a manner such that automatic trip ping of a single pole ormanual tripping of all poles may be obtained. The interlocked diaphragmvalves serve, in addition, to protect the main air storage tank so thatthe entire charge of air contained therein will not be lost during acircuit breaker interruption.

Reclosing of the-breakers is automatically obtained if the circuitbreaker opening has been a result of a temporary mercury arc rectifierfault such asa back fire, but closure of all of the rectifier poles isobtained by having another interlocked control system which in thisinstance is an air manifold joining the reclosing means of all of theanode breakers.

It is therefore an object of my invention to provide a high specdsinglepole circuit breaker, particularly adapted for operation in the anodelead of a mercury arc rectifier.

Another object of my invention is to provide I means for effectivelyinterlocking a plurality of single pole circuit breakers.

Still another object of my invention is to provide a plurality ofcircuit interrupters which are efi'ectively interlocked; whichinterlocking per-.

mits independent operation of a single pole when required by thecircuit.

A still further .object of my invention is to i provide a circuitinterrupter which operates to interrupt single anode faults withoutnecessarily disconnecting the entire rectifier from the circuit.

Still a further object of my invention is to provide a circuitinterrupter which will interrupt momentary faults due to backfiresinmercury arc rectifier operation and which will isolate'the mercury arcrectifier if a permanent fault has occurred therein.

It is still a further object of my invention to interlock the pluralityof single pole anode circuit breakers by means of a compressed airopening and reclosing system and a plurality of electrical switchingdevices for operating the same.

These and other objects will become apparent from the followingspecification taken in con-- which:

single pole circuit breaker and the means for interlocking the same witha plurality of similar poles.

Figure 1a. is an enlarged view of part of the circuit breaker shown inFigure 1.

Figure 2 is a fragmentary view of one of the control switches operableby the circuit breaker taken along the line 2--2 of Figure 1.

Figure 3 is a cross-sectional view of a single pole-circuit breakertaken along the line 3-3 of Figure 1. i e

Figure 4 is a fragmentary cross-sectional view of the over-load magnetand adjusting means therefor taken along the line 44 of Figure 1.

Figure 5 is a broken cross-sectional view of the circuit breakertripping manifold taken along the line 5-5 of Figure 1.

Figure 6 is an enlarged cross-sectional view of the check valve operablewithin the air manifold 7 taken along the line 6-8 of Figure 5.

Figure 7 is a supplementary view of the check valve taken along the line1+1 of Figure 6.

Figure 8 is a cross-sectional view of the single pole circuit breakerindicating the involute air passage surrounding the circuit breakercontacts I Figure 11 is a fragmentary cross-sectional view taken alongline iI--l| of Figure 10.

Figure 12 is a schematic representation of the plurality of anodecircuit breakers and the control means therefor.

Figure 13 is a schematic representation of one modification of thecontrolling system of Figure Figure 14 is a fragmentary schematic viewof a counting system operable for circuit breaker control.

Figure 15 is a fragmentary schematic view of the over current magnet andillustrates one form of polarizing coil for reverse current tripping.

In Figure 1 there is shown a single pole circuit breaker which is oneelement of a plurality of interconnected poles operable within the anodeleads of a mercury arc rectifier. Figure 15 schematically indicates atypical installation which in this instance includes a six-phase mercuryarc rectifier employing in 'each of the anode leads, a circuit breakerelement of the type indicated in Figure 1.

The rectifier anodes are fed from a six-phase star connected "secondary2| of a transformer, the de ta connected primary 2! of which is fed froma three-phase alternating current transmission \9 into the casting 38 ismore clearly illustrated in Figures 3 and 8 wherein it may be seen thatthe passage lz is a cored involute, spiralling to com-. pletely surroundthe contact 3| as indicated in Figures 1 and 3. Thus, air entering intothe passage 82 will be conducted to the contact 3| and the air stream aswil1 hereinafter be indicated. The plurality 1 of circuit breakerelements employed are interconnected to effect the desired circuitinterruptions for mercury arc rectifier operation.

The exact nature of the single pole circuit therefor will now bedescribed and reference is now made to the cross sectional views of thesingle pole breaker. Figures 1 and 112. i

The single pole of the-circuit breaker illuswill completely surround thecontact.

Returning now to the air control means, that is, the diaphragm valve"illustrated in Figure 1. it may be seen that air flow in the coredpassage 52 is controlled by the position of the valve seat I breaker andof the tripping and control means trated consists essentially of twocooperable contacts. Sl'and J2, and means for directing and Icontrolling an air blast which enters through the pipe I3 and passesover the separated contacts during circuit interruption. The pluralityof circult breakers which are required for the various rectifier anodeleads may all be mounted directly upon a common storage tank to shortenand thus .facilitate piping connectionsthereto as indicatedschematically in Figure 12. That is, the base 34 of the flange 88 may becoupled by belts or other suitable means directly to an air storage tankwhich ischarged by means of a compressor. The

sysi'lc'ams may beadjusted so that pressure therein remains withinpredetermined limits and that any variations of pressure outside ofthese limits may operate to open the circuit breakers.

rThe main metallic casting 38 of the circuit" breaker is, as willhereinafter be shown. at a relatively high potential and it is thereforenecessary to electrically isolate the casting from ground potential.Therefore, the casting 38 is supported upon the air storage tank bymeans of a pipe 83 made of a suitable insulating material and of'sufllcient length to ensure a minimum of leakage and to preclude thepossibility of an are material 54 relative to the edge I! of theinwardly projecting pipe 8 I The valve diaphragm is supported upon themetallic casting 38. in a counter-bored recess 88 in the wall of thecasting. The diaphragm 48 is a circular piece of flexible material suchas rubber and is held in the counterbore 85 by means of a circulardomeshaped member 58 which is turned down at 81 to correspond with theinner diameter of the counter bore 85.

The dome shaped member 88 is then securely fastened to the main casting38 by means of a plurality of machine screws 8| which are circularlydisposed as is more clearly indicated in the rear view (Figure 5) of thedome shaped member 88.

, The machine screws 8| pass through a corresponding set of perforations82 in the dome shaped member and engage threaded perforations 83 withinthe main casting 38. The valve diaphragm 46 is thus securely clampedbetween between the circuit breaker frame and the air storage tank. vThe base of the'casting I8 is preferably a circular external flange 81which is supported upon the pipe 83 and thus upon the air storage tank.by means ofthe. piping flange 4| which is in screw thread engagement at42 with the insulating pipe .38. The 'extemal flange 3'! of the casting38 may then be fastened to the piping flange by any convenient means, asfor instance, a plurality of machine screws, but first an annular gasket43 T is inserted therebetween to preclude the leakage of air at thejunction of the surfaces. g

A taperedopening 44 of diameter equal to the inner diameter of theinsulating pipe 38 admits to the casting 38 air which is then conductedthrough the cored passage 48 to the controllable diaphragm valve 48. e

The cored passage 48 terminates in an annular air passage 41 whichcompletely surrounds the diaphragm valve 48. Aligned with the valve is aprojecting circull l'pipe 8! which provides a passage 82 for directingthe incoming air to the contacts SI and 32.

The end surface 58 of the inwardly projectin pipe I} is smoothed tocooperate with a layer 84 of valve seat material which iscarried by thevalve diaphragm 48.

The passage '82 provided by the annular metallic projection 8 l whichhas been integrally molded the projection 51 and the main casting 38. Inorder to assume an air tight joint at this point and to prevent radialmovement of the edge of the diaphragm when subjected to air pressure, awedge shaped circular protrusion 84 on the projection 51 is forced intothe resilient material of the diaphragm when the screws 8| aretightened.

The member 88 has been machined to provide the spherical dome 85 andthusaxial displacements of the diaphragm 48 are limitedlto the space betweenthe dome 88 and theend 88 of the inwardly projecting cored pipe 8 I. Thevalve diaphragm 48. is of flexible material and has secured to it twocircular metallic disks 88 and 81 on either side of the flexiblematerial. The face of disk 81 is faced with a valve seat material. whichwill provide a suitably close surface engagement with the end 58 of theinwardly projecting passage. therefore which comprise the movableportion of the valve are bound together by the screw 'li and itsassociated nut 12 which bears against a conical shaped metallic member13 whichv assists in directing the flow of air toward the discharge whenthe valve is open. I

The rear face I4 of the metallic disk 88 has been machined to correspondwith the dome shaped chamber 65. Thus it may be seen that the inflowingair which enters through the insulating pipe 33 is guided to the annularcored passage 41 surrounding the inwardly projecting pipe II and theface of the diaphragm valve. It now the diaphragm 48 is displaced to theleft, as viewed in Figure 1, the air will, as indicated by'the arrow 4heads of Figure 1 enter from the passage 48 and valve 48 will controlthecircuit breaker blast and will be discussed in greater detail in laterparagraphs inasmuch as the structural details of the circuit breakerwill now be described.

The four layers of material,

I Contact 3| is aconically shaped butt contact engageable with a nozzleshaped contact 32 along the contact surfaces 3| and 32' which have beenfaced with a suitable contact material such as ,a non-welding alloy oftungsten and silver, silver and graphite, or the like.

"Nozzle shaped contact 32 is fixed relative to the main frame 36 of thecircuit breaker whereas contact 3| is slidable relative thereto. Asindicated in Figures 1 and 3, contact 3| has been displaced from itsclosed position and thus the air flow is indicated by the arrow heads.As the blast air approaches the contacts through a spirally shapedpassage 62, as indicated in Figure 8, the air flow about contact 3| willbe in the form of a vortex while passing outwardly through nozzle shapedcontact 32. Therefore, an are which is drawn between contact faces 3|and 32' as a result of contact separation will be spun about the contactsurfaces. This action will facilitate cooling and decrease thepossibilities of contacts 3| and 32 welding. The spinning-air exhaustingbetween the contact surfaces and through contact 32 isillustrated sche--matically by the arrow heads in Figures 1 and 3.

Nozzle shaped contact 32 is supported within a circular opening" whichis formed within a projecting extension I6 of the main casting 36.

As will be pointed out in later paragraphs, the main frame 36 is at thepotential of contact 3| and therefore it is necessary to support contact32 within the opening I5 by suitable means of insulating material.Contact 32 is secured between the line terminal 11 and the exhaust pipeand muiller 6I and 62. This assembly is made rigid by, an externalflange 66 on the out'er'end of contact 32 nesting within counterbores 66in terminals I1 and 66 in exhaust pipe 6| so that when the parts areassembled as indicated in the plurality of nuts 6| which as in Figures 1and 3 serve to clamp the exhaust pipe to the terminal 11 which is alsoindicated in Figure 10.

The assembly of contact 32, terminal 11 and exhaust pipe 6| is thenclamped to the main casting 36 by means of a plurality of socket headscrews 62 more clearly indicated in Figures 10 and 11. That is, lineterminal 11 provides a series of perforations 63 through which thesocket head screws 62 may pass into a corresponding tapped perforation66 in the main casting 36.

It hasbeen previously pointed out that it is essential to insulate lineterminal 11 from the' main frame 36 inasmuch as frame 36 is at thepotential of contact 3| and line terminal 11 is at the potential ofcontact 32. Therefo e, the socket head screws 62 have been sheathed ininsulation, that is, a cylindrical tube of insulation 66 has beenprovided to prevent the shank of the bolt from contacting terminal 11and the head of the bolt has been similarly protected by a cylindricalcup 66 which has been perforated at 61 to allow the passage of theinsulating tube It should be noted that if desirable, the various tubesof insulating material may be disframe 36 and the line terminal 11, acylindrical tube I63 is cemented to the insulating plate I6I atperforation I66 and is of an outside diameter equal to the innerdiameter of the passage v16 in the main frame 36. Therefore, when thecontact 32 is secured by means of flange 63 between the line terminal 11and the exhaust pipe 6| and this entire assembly is subsequently clampedto the main frame as indicated in Figure 1', along with the insulatingplate IM and the insulating cylinder I63,'contact 32 will proiect intothe passage 16 and will be centrally located with respect to thespirally oriented air passage 62.'

' It should be noted that the outer cylindrical surface of the contact32 has been turned down at I66 to provide an airgap I66 between theinsulating tube I63 and the face of the contact 32 which is at thepotential of line terminal 11.

This, in effect, provides an increased leakage p'ath and thereforereduces the possibility'of electrical break-down at this point.

The nozzle shaped passage I61 of the contact 32 provides for theexpansion of the blast air in order to .reduce back pressure.

Exhaust pipe 6| juxtaposed against contact 32 along the face IIIprovides a tapering passage which is a. continuation of the taperingpassage of the low pressure side of the nozzle. The pipe supports, bymeans of the screw threads II2, the hollow cylindrical muiller 62 andthe deionizing stack II3. This stack comprises a. plurality of 66parallel metal laminations over which the hot are products pass and areeffectively cooled,

Conical contact 3| is mounted upon a piston I I6 which is slidablewithin a cylinder H5 in the main casting 36. In order to prevent leakageof air over the piston II6, a series of grooves II6 have been turned inthe piston and piston rings 'or other packing may be inserted therein.

The contact 3| is centered on the piston II6 by a boss extending into aperforation I I1 and is clamped thereto by means of the screw threadedplunger rod I2 I. This rod has been turned down and threaded at the endI22 which engages a tapped perforation in the contact 3|. By tighteningthese threads, the annular flange I23 is brought into contact with aflexible conductor I26 which has been perforated at I26 to allowthepassage of the plunger rod I2I. Therefore, bringing plunger rod I2I intoscrew thread engagement with the perforation in 3| will securely clampthe assembly of contact 3|, piston H6 and flexible conductor I26. I

The movement of piston H6 is limited by the engagement of contact faces3| and 32' at one end of the stroke (at which time the circuit is-closed) to the engagement of the rear face of the piston with a ringshaped rubber or other flexible .washer I26 which has been securedwithin a reentrant flange I21, molded into the main casting plunger rodI2I and thus when cl this flange has been cut away at I! to allow forthe passage of the flexible conductor I24.

Piston II4 therefore which is operable within the chamber II5 betweenthe limits of engagement with the stationary contact and the annularrubber ring I26, is the operating element of the circuit breaker, thatis, operation of the pis-' ton I I4 in either direction by means of airpressure controlled by diaphragm valve 46 or any of the other valveswhich will hereinafter be discussed, will operate either to open orclose the circuit.

Contact 3| is connected to the external circuit through the flexibleconductorI24 which allows movement without in any way impeding movementof the piston. The flexible conductor I24 is composed of a series ofhighly conductive metal laminations stacked together by suitable meansand'is fastened at either end .to a bifurcated member by means of theplurality of machined screws I32. The bifurcated ,member I33 thencontinues downward to engage the line terminal I34 and the cable I35from the external circuit by means of the bolt or other fastening meansI36.

Supported b the flange I21 is a. member I which positions the plungerrod I2 I. The member I4I contains a cylinder I42 in which is operable apiston I 43 and its associated packing I44 mounted on the end of theplunger.

Secured in one end of the cylinder I42 is a flanged bushing I5I which inthis embodiment is fastened by the screw thread I52. A perforation I53allows the passage of the plunger rod I2I but this perforation is withina reentrant 'flange I54 for reasons which will be pointed out in afollowing paragraph.

A flange I55 on the plunger rod I2I which originally had been machinedcircular similar to the flange I23 is milled off so that it may engagethe rectangular cross section of a Ushaped channel I53 as indicated inFigures 1 and 3.

The piston I43 is drilled at I51 to allow the passage of plunger rod I2Iwhich is then clamped thereto by means of the nut I8I. Prior to theapplication of the nut, however, a series of fiber or other type ofwashers I44 are slipped over the ped by nut I8I provide the necessaryair tighttpacking for piston I43. The U-shaped channel? I53 is heldaeoaoee a as between the flange I and the piston I43 and is allowed toextend out through the axial perforation'I62 in member I4I so that itmay cooperate with the switching member I63 which willher'einafter bedescribed.

Contact 3I is biased normally towardsthe open position, that is, theposition corresponding to contact between the rear ofthe piston Ill andv is normally under compression, and as the reentrant flange I54 isfixed, there-isa tendency to draw contact 3I from engagement withcontact 32. a

"The outer end of the closing cylinder casting is provided, at its loweredge, with a pair of horizontal lugs I63. The-bifurcated member I33,which is also=the over-currentibus bar, is suppoi-ted against the bottomof these lugs by studs threaded into the bar, passing through holes in,.the lugs and held in position by nuts and lock washers I10. The lowerend of the bar is braced by the member I33, asyu be fdescribedin afollowing paragraph. j

The forked conductor I 33 support upon a protrusion, the plurality of,machine screws-m which pass through magnet laminations I12. The magnetis composed of stacked soft iron or other magnetic laminations each ofwhich: is horse-shoe shaped and as such surrounds the magnet bus bar I13(see Figure 4") whichis an integral extension of the forked memberI33Lfns it is desirable to preclude the possibilityfof cur}? rentflowing through the magnet,thefscre 1i are insulated by means ofinsulating sh" which completely surround their res cti e screws. j

Referring now to Figure l WhlC fllS I sectional view of the magnet andmagnet'bus bar I13, it may be seen that the magnet bus passes directlythrough the horse-shoe" shaped magnet formed by the stacked laminations.The ar mature I13 of this magnet is a trapezoidal laminated bar ofmagnetic material which is carried upon a plunger I11.

The operation of the magnet may be explainedbriefly by noting that theline current will flow through the bus bar indicated in Figure 4, andwill establish a cylindrical magnetic field sur rounding the conductoritself. Therefore, the stacked laininations comprise a magnetic circuitfor the flux in the vicinity thereof and accordingly the faces I8I andI82 act as magnet poles and exert a force of attraction upon the wedgeshaped armature I16.

It is frequently desirable particularly in the ergized by a constantvoltage. The force exerted upon armature I16 due to the flux ofthispolarizing coil is'in the same sense as the force which -willbeexerted by the flux produced as a result of reverse current flowingthrough bus bar I13.

The polarizing flux alone is insufficient to cause displacement ofarmature I13, but maybe adjusted so that relatively small reversecurrents will result in actuation thereof to open the ci'r-' cultbreaker. The application of a polarizing coil does not prevent normaloperation of magnet upon forward currents. I

As indicated in Figure 1, the magnet bus I13 which may, during shortcircuit periods carry considerable currents, is braced so as topreclude.

any mechanical deformation thereof due to the stresses developed byvirtue of the magnetic forces. The brace comprises the metallic niemberI33 which has been fastened by means of machine screws I84 to theframe'of casing 33 and by means of the plurality of machine screws andbolts I85 to'the magnet bus. This brace is insulated from the flange 31-by insulating layer I33; however, the brace itself may be formed froman insulating materiaL' The electromagnetic device I12 in conjunctionwith the armature I16: controls the diaphragm valve 46 to control theadmission of air to the contact chamber. The plunger rod I11operatesunder the' influence of the magnet 1 12 and in order that therod I11 be maintained" in alignment. it passes through a perforation I33within the magnet lamination stack and through a perforation I31 in themagnet bus bar I13.

The armature I16 is clamped securely to the rod I11 between the flangeI19 and nut I9I which engages a-series of screw threads on rod I11. Therod I11 is continuously biased towards the right as' viewed in Figures 1and 4, by means included within the cylindrical member I93.

The cylindrical member I93 is fastened to the main frame 30 through thedome shaped member 56 by means of the screw threads I94 upon both thecylindrical member and a corresponding hollow in the rear of the domeshaped member.

However, inserted into the hollow of the dome shaped member prior to theinsertion of the hoi- 5 low cylindrical member I93, is a small circularmetal piece I95 which contains a conical valve seat I96 and acylindrical perforation I91 to permit the passage of air from thediaphragm valve. The conical projection of the circular metal member I95provides for surface engagement-with a layer of valve seat material 20Iwhich is embedded in a metallic disk 202 which is integral with the endof the rod I11.

The disk 202 is machined to correspond with the inner wall of the hollowcylindrical member I93 so that it is maintained central at all times.

The hollow cylindrical member I93 is terminated by a metal stop 203which is fastened thereto by means of the engaging screw threads 204 andwhich is perforated centrally at 205 to permit the free operation of rodI11.

It should be noted that bearings are provided for rod I11by theperforations within the bus bar and in the metal stop 203. The biasingmeans for rod I11 is obtained by springs acting between the metal disk202 and stationary members. 1 Thus a small diameter central spring 206bears against both the inner face of disk 202 and the inner face of themetal stop 203. This spring is of relatively small diameter and fitsover the rod I11 which thus acts as a guide therefor.

A second and adjustable spring 201 bears against the inner face of thedisk 202 and also '45 against a movable or adjustable-guide 2I I. Theguide 2 is a ring shaped metallic member having a' perforation 2I2 ofdiameter large enough to pass over the spring 205 but small enough toprovide a seat for the end of the spring 201. The 5 ring 2| I isslidably fitted within the hollow cylindrical member I93 and is adjustedtherein by means of a. plurality of fins 2I3 which project through axialslots 2|4 in the walls of the cylinp drical member I93.

These fins may comprise merely two pins which have been embedded in thering shaped member 2! I and project from the axial slots 2 I4. As bothspring 200 and spring 201 are continuously under compression, there willbe a tendency to move disk 202 and its attached rod'I11 to the right asviewed in Figure 1. The magnitude of this tendency is controllable bymeans of the adjustable nature of spring 201. That is, by threading theouter'surface 2I5 of the hollow cylindrical member I93 and passing a nut2I6 thereover and in engagement with the threads 2 I5, the fins 2t3 maybedisplaced axially upon rotation of the nut 2I'6. Thus the compressionof spring 201 will vary with the position of nut 2I6.

Obviously, therefore, the variation in the compression forces of spring201 will accordingly vary the biasing force of rod I11 and itsassociated magnetic armature I13. As will be indicated in the following,the magnet I10 when operated 75 'shaped under side of the valve.

controls the operation of contacts 3I and 32. Accordin'gly, anadjustment of either the air gap or restraining force on the armatureI15 will correspondingly vary the magnetic forces required to displacethe same and thus operate the circuit breaker. This then provides anadjustment for the tripping current required.

Two small control switches are actuated by the rods I63 and I11. Theswitches as more clearly indicated in Figure 2 are mounted uponinsulating brackets such as 2. and 2 I3. The switches operable by theircontact carrying rods are essentially butt contact switches employing ametallic bridge to complete the circuit between the 4 two contacts. Thusas indicated in Figure 2, the rod I63 carries the bridging metallicmember 22I which is engageable with the two butt contacts 222mm 223.

The rod I63 passe througha perforation 224 within an insulating member223 and thus is maintained in slidable relation therewith. The entireswitch is clamped to the insulating bracket 2I1 by means of the screwsand bolts 223.

When the circuit breaker contacts 3,l and 32 are closed, switch I63 isin the open circuit position. On the other hand, when rod I11 is biasedso that valve seat material comes into contact with the metallic insertI95, the switch 23I is in the closed circuit position.

When contacts 3I and 32 are closed, current flows from the bus bar orother electrical connection 235 which is bolted to the line terminal 11bus by means of the bolts 236, through the engaged contacts and thenthrough the flexible conductor I24 to the tine of the bifurcated memberI33, then through the magnet'bus bar I13 and out through the cable orbus bar- I33 fastened thereto. 9

Under closed circuit conditions and no electri- 0 cal disturbances, thefull tank pressure will exist in the passage 45 and the annular coredchamber 41 on one side of the diaphragm valve 46 and also in thechamberbetween the valve 43 and the domeshaped member 53. Under theseconditions of equalized unit pressure on both sides, the valve 46 willbe displaced more to the right as viewed in Figure 1 inasmuch as theleft side of the valve has a considerably larger area than the ring-Therefore, with equal unit pressures on both sides of the diaphragm, thevalve seat material 54 will be forced into engagement with the end ofthe projecting. passage 52 and thus cut off the supply of air theinvoiute passage surrounding the contacts. $5; The contacts 3I and 32are maintained in engagement allowing full air pressure. to beestablished within the chamber 236 which will thus actuate piston I44and rod |2I in a direction which will close the contacts against theaction of the biasing compression spring I34.

However, the removal of valve disk 34 from contact with the projectingpipe 53 will allow full pressure to be built up in the involute passage32 toithe contacts 3I and 32.

From Figures 1 and 3, it may be seen that piston I, which is fixedrelative to contact 3I is of considerably larger diameter than thepiston I43 and therefore without necessarily releasing the pressure inthe chamber 233, the contact 3| will be displaced to the left as viewedin Figure l.

Full tank pressure is maintained in the chamber 236by means of theclosing manifold 231. which connects the air from the storage tank toeach of the single pole circuit'breakers controlled therefrom. Themanifold 231 itself may com-I.

a circuit breaker.

1 The clamping bracket 243 prise a Bakelite tubing perforated at 2 toallow the admission of air to and from chamber 266' and the entiremanifold as indicated injigure 3 i supported between two clampingbrackets 242 and 246 which are maintained in fixed relation by Thenature of the manifold mounting is indi-' cated in Figure 9 which is anend view of the The clamping action is secured by means of the bolts 244as previously mentioned which pass through suitable lugs cast into theclamping bracket 242. The semi-cylindrical depression 245 in the clamp243 which surrounds the air passage 24I which has been cut intothemanifold 231 must be lined with a suitable gasket 246 to prevent leakagetherefrom.

must, in addition to the semi-cylindrical depression 245, contain aperforation 241 which will allow the entrance of air to the chamber 266.Again, to prevent air leakage, the surface contact between the clampingbracket 243 and the hollow cylindrical member I4I must be sealed with asuitable gasket 25 I Th blast valve control manifold 255 is supported bymeans of a semi-cylindrical clamp 256 upon a boss 251 integrally formedon the dome shaped member 56. The boss 251 has been me.-

chined to accommodate the cylindrical manifold 255 which isrigidlyclamped thereto by means of relatively large perforation 2" which hasbeen formed therein. It should be noted from Figure 6 that theperforation 21I is relatively large when the plurality of bolts 26Iwhich pass through suitable perforations in both the clamp and the domeshaped member. The manifold 255 comprises a Bakelite or other suitableinsulating.

Y gasket 262 as is more clearly illustrated in the enlarged fragmentaryview of the tripping manifold Figure 6.

The tripping manifold 255 is connected by air passages to the controldiaphragm valve 46 and the valve 2M which is operated by theelectromagnetic device I16. A perforation 266 in the tripping manifoldis connected by means of the duct 264 to the nozzle I61, formed in themetallic disk I65, which forms the seat for the valve disk 26L 7 Thecylindrical opening I61 and the conical tapering opening I66 have, inadditionybeen joined to the innerportion of the dome shaped member 56 bymeans of'a circular array of holes 265 and thus duct 264 is effectivelyinterconnected withathe space between the dome shaped member 56 and thediaphragm valve 46, whether the valve 26I is open or closed. The portionof duct 264 projecting into-the nozzle shaped opening in disk :95has'been designed so that-an as"- pirating effect is secured when airflows through duct 264 and through opening I61, to-drawthe air throughholes 265 when valve 26I is opened.

An additional air passage is provided from the manifold tovthe domespace by means of a duct 266,-more clearly illustrated in Figure 6,- andthe flow of air through this duct is controlled by a check valve 261formed in the rubber gasket 262.

Asseen in Figure 5, this duct is displaced sidemanifolds.

also exists in the passage 45 and in the annular comparedto the duct266.

This valve is formed by cutting two parallel slits 212 into the gasketon either side of the duct 266 as indicated in the fragmentary view ofFig- The diameter of the larger perforation 21I in the manifold isgreater thanthat of the spacing between the two slits." Therefore, whenthe pressure in the manifold 255 is low, as compared with the pressureof the air within the dome; there will be a tendency for the air-toflow, as indicated by the arrow heads in Figure 6, in a manner such thatthe flexible material contained between the slits 212 will bend asindicated and thus allow air to pass around the slits and into themanifold. I

On the other hand, if the pressure in the man-'- ifold 255 is greaterthan the pressure within the dome, there will be a tendency to force theflexible material, between the slits, up against the smaller duct 265and thus effectively check the flow of air through the duct. The reasonsfor thisarrangement will be taken up in the following paragraphs.

When the circuit breaker is connected in circuit with the anodes of therectifier as in Figure 15, and all the poles are closed, the individualpoles are interconnected by;the manifolds 261, and 255, the full tankpressure will exist in both Therefore, as a. full tank pressure chamber41,-the diaphragm 46 will be moved as determined by the side having thegreater sur-.

face area.

This obviously is the side which is adjacent the dome shaped member 56as the area of the 'valve disk covering the blast pipe is at atmosepheric pressure. Full". tank pressure exists between diaphragm 46 andthe inner wall of the member 56 inasmuch as this chamber is connedtedwith the tripping manifold 255 through the duct 266 and the plurality.of perforations 265. It should be recalled that for normal conditions ofoperation (that is, values of current up to the current'for which thearmature is adjusted) that the valve 26I is normally biased toengagement with the disk I95 and therefore the air within the dome andwithin the tripping manifold does not escape. Should a fault occur onthe anode to which the pole under discussion is connected, the armatureI16 would be actuated to the left as viewed in Figure 1 under theiniluence of magnet I12, and the v'alve 26I will be removed from surfaceengagement with the disk I95.

This will immediately allow the air contairfed within the dome toexhaust through the plurality of openings 265 and through the nozzleshaped valve 26I and then through the perforations 2 within the wall ofthe hollow cylindrical member I In addition to, this escape air which isflowing through opening I61, air will flow from the tripping manifoldthrough the duct 264 and out through the opening I61. Inasmuch as thisoutflowing air is at a high pressure, means must be provided to preventit from reducing the velocity flow from the dome through this passage.aspirating eii'ect has been arranged in order to increase the. velocityof the air flowing from the The' valve 46 to the left as indicated inFigure 1 and accordingly allow the main air blast entering from thetank, upon which the breaker is mounted, to flow into the involutepassage 52. The increase in pressure within the passage 52 will operateupon the relatively large diameter piston H4 and will thus force contactII to the left against the action. of the high pressure air upon thesmall diameter piston I43.

Immediately thereafter an arc will be. drawn between contacts 3| and 32which will be extinguished by means of the high velocityair blast whichis in this instance a rotating or spinning air blast.

The heated air will exhaust through the nozzle shaped contact 32 and itsassociatedextension 8 I. Upon flowing through the mufller 82, the airstream will be cooled by the stack H3 which, as previously described,comprises a parallel stack of spaced metal plates. v

During the operation of; the circuit breaker under the influence of anoverload or fault current two other important operations are per--formed in the following sequence. First, upon the actuation of magnetarmature I18, the switch 23| is opened, and second, immediatelyfollowing the displacement of contact 3| to the left, the

' contacts of switch 221 are closed.

The position of the armature I16 is deteYmined by the current flowingthrough the magnet bus bar H3 and therefore immediately followingcurrent interruption. the force upon armature I16 willvanish andtherefore the armature I16 will again be solely under the influence ofthe biasing springs 206 and 201.

The springs will carry the valve disk 20! .intb engagement with themetallic member I95. It is important to note that the springs 206 and201 must supply suflicient biasing force to close the valve althoughfull tank pressure exists within the opening m. The reclosure of valveam will,

through ducts 264 and the plurality of openings 265, cause the pressureto the rear of diaphragm 46 to build up to the full tank pressurewhereupon the diaphragm valve will immediately close and thus cut of!the supply of air flowing through the involute passage 52. I

This precaution has been taken, to preclude the possibility of the airstored within the tankfrom completely "discharging through the chamber52 and its associated exhaust passages. Again, assuming that no otherexternal influences have acted upon the circuit breaker, the removal ofthe air supply from ichamber 52 will effectively decrease the pressuretherein and accordingly if the full pressure still exists within theclosing manifold 23! air will flow to operate the piston I43 and itsassociated piston rod- I to the right as viewed inFigure l to'closecontacts 3i and 32 and thus complete the circuit which had beeninterrupted by means of the automatic'electromagnetic tripping device I12. 2

The cycle of events described/immediately above concerning the operationof the circuit breaker under the influence of an overload assumed thatthe pressures in the two manifolds 231 and 255 remained at the storagetank value.

The nature of the changes occurring in the pneumaticallygoperatedcontrol system will now be described with reference to the operation ofa series of single pole'circuit breakers, each oi which is in circuitwithan anode of a mercury arc rectifier.

. The complete control system for a circuit breaker of which Figure l isa typical example, comprises means for manually and automaticallycompleting the circuit to all of the anodes simultaneously. In addition,it contains a plurality of protective features such as under pressuretrippressure within predetermined limits by means of j an aircompressor.-

The six single pole circuit breakers, which have been schematicallyrepresented, are indicated by the numerals 302-301 but to facilitate thefollowing description of the operation of the controlling system, thepole 301 has been drawn to be a diagrammatic representation of the poleof Figure 1. 1

In carrying Over the reference numerals applied in Figure l, the currententers the pole 301 through the bus bar as which is joined to thecontact 32 mounted upon an insulator IM within the main casting 36.Cooperating contact 3| is mounted upon a piston I H which is in turn inoperative relation with smaller diameter piston I43 through rod l2l.From contact II the current is carried by the flexible conducto I24, bybar. I13

through the "horse-shoe magnet I12, and thus to the bus bar I35.

The armature H8 is in operative relation with the magnet I12 and iscarried uponthe plunger rod I" which in turn carries the valve 21. Thediaphragm valve 48 controls the air stream entering through chamber 45to passage 52 which surrounds the contacts. The tripping manifold 255communicates with each of the domes formed between member 56 and thediaphragm l6; and the closing manifold 231 communicates with each of theclosing cylinders and associated piston, I. The switches 221 and 2 areoperated by the plunger rods I 2| 0! the breaker contact and I'll of thearmature respectively. The circuit breaker 301 is illustrated as trippedand having been caused to remain open. However, it should be 4 notedthat the valve 20! has been closed and that therefore diaphragm l6has'been displaced under the influence of air entering the dome from themanifold 255 to shut oi! the blast air.

Ai is supplied to the tripping manifold 25! through a tap 3 from themain storage tank through an electromagneticallybperated valve M2. The.members 313. at each of the pol -s represent the junction between themanifold 25! and the diaphragmvalve 4B of each of the poles. The controlsystem is electrically operated from a direct current source which maybe copper-oxide rectiflers, batteries or the like, and has beenschematically illustrated by the battery M2.

The valve 3|2 is controllable bymeans oLthe electromagnetic device whichin Figure 12 is schematically illustrated as a plunger type solenoid ll5which in the circuit indicated is operated One of these control linesoriginates at the ne aed upon each of the circuit breakers.

sization thereof.

tive control bus bar and contains in series therewith the plurality ofswitches 22'! each of which is operated by the piston rod !2! of itsassociated circuit breaker. u

From the plurality of series switches :21 the.

electrical circuit then passes through relay 3l6 and solenoid 3! 5 andthen terminates at the positive bus bar.- A second circuit alsooriginates at the negative control bus bar and then contains graphs. V

In series with these three switches are the plurality of switches 23!one of which is mount- At the termination of these switches, the controlline extends to the positive bus through the relay 313 and the solenoid3 I 5.

There are, therefore, two parallel circuits for controlling the relay3l6 and the solenoid M5, and either circuit will be effective for theenerplurality of switches Therefore; if one or more switches in Eachcircuit comprises a in series.

' each of these circuits are opened, the relay and other circuit. Uponthe opening of all the circult breaker poles, a circuit is completedthrough all the switches 22'! for purposes to be described later.

Solenoid -3|5 when in the energizedposition as indicated in Figure 12allows passage of air from tank 30! to the tripping manifold 255 andthus permits the entry of air into the-space between the dome shapedmember 55 and the diaphra m valve 43. However, when in the deenergizedposition, the schematically representedplunger 324 will be actuated bythe spring 325 to allow the high pressure air within the trippingmanifold 255 to exhaust through the indentation 326 contained therein.The operation of solenoid 3l5 will not permit the escape of air throughthe coupling 32] within the valve and thus will not permit the escape ofair storedwithin the tank.

The closing manifold 23'! utilizes the compressed air of the storagetank 30! taken at the tap 3!! through pipe 33!.

cally operated valve 332 controls the influx of air thereto and when thesolenoid 33!! is in the de nenergized position .as indicated in Figure12, the

An electromagnetiis open circuited when the contacts 3! and 32 are inengagement and the switching elements 23! contained on each of theseelements are in the closed circuit position, during normal conditions.

Therefore, when the circuit breaker is in the closed circuit position,the switches 22! do not control the operation ofthe electromagneticdevice 3!5. If normal conditions prevail, the

switches 23! and the switches 32!, 322 and 323 will all be closed andthe electromagnetic device 3!5 will be energized and the plunger 324will be in the position indicated in Fi ure 12.

. This allows air pressure to be built up within the The spring 3331semployed to depress the solenoid plunger 335 wlien the electromagneticdevice ls deenergized. Inthe energized position, the

perforation 34! within the solenoid plunger permits the flow of air fromthe tank 33! to the closm8 manifold 231.

Joined to the closing manifold is a relief valve 342 whichmay beemployed to vent the closing manifold. 'When this valve is'open,accidental closing of the circuit breaker contacts is impossible.

It is to be recalled from the construction of the single element of thecircuit breaker as indipressure drop within the dome.

When the tripping manifold is vented by th deenergization of solenoid3l5, air flows from the dome through. the manifold and to the atmospherethrough the passage 264. The check valve in the tripping manifold 254assists in the release of the dome pressure since it permits the flow ofair from the dome through relatively short passage 233 (as illustratedin Figure 6) to the manifold. The check valve, therefore, functions toaccelerate circuit interruption accomplished by the opening of switches32 -323.

Energization of any one of the trip magnets will causevalve 20!instantaneously to vent its associated dome and cause the main contactsof the breaker to separate. Since valve 2!!! is mechanicall'yinterconnected with switch 23!, displacement thereof to vent the domewill cause deenergization of solenoid 3l5, venting of trip manifold25,5, and subsequent opening of all the other poles of the circuitbreaker.

It is desirable to reenergize, the electromagnetic device 3I5immediately after circuit interruptions so that the valve diaphragm 46may reclose and preclude the exhaustion of the air within the storagetank 30!. v

' If tripping occurs due to overcurrent on one 'of the poles (or reversecurrent, when a polarizing magnet coil is employed), and thus due to amovement of one of the switches 23!, reenergi- .zation of theelectromagnetic device 3l5 will ocoperation of one of the three switches32!, 322

and 323, it is necessary to provide other neans for reenergizingelectromagnetic device 3! 5 inorder to reclose the diaphragm valves 45to preclude the escape of the entire charge of thestorage tank. Thesemeans will be described subsequent to the description of the switches32!, 322

and 323. i

Inasmuch as the circuit into which these three switches are connectedcontrols the tripping of the circuit breakers, these switches areutilized to provide manual and other types of automatically.

operating systems, as follows:

Switch :2! is a normally closed mama-(a1 cited in Flgure 1, that theswitching ember 22! erated push button. It provides for .a hand trip L 3asoaoec whenever it is necessary to shut down the rectifier or otherapparatus connected thereto.

Switch 322 is controlled by a pressure guage mounted upon thestoragetank. Thus if the pressure within this tank falls to the minimum valuerequired for effective and rapid circuit breaker operation, this contactwill interrupt the circuit.

Switch 323 is controlled by a circuit breaker or disconnect switchconnected in any other circuit of the rectifier or associated apparatus.Thus, .if other switching means is operated or an undesirable conditionarises, it may be necessary to shut-down the complete system.

Additional switches may be added to the control line comprising thethree above describedswitches and the switches 23! which are mountedupon individual circuit breaker elements, in order that other deviceswithin the system may control the operation of the anode circuit, ifnecessary.

Since these three switches may operate and remain in their open circuitposition, it is necessary as previously mentioned to provide meansoperative to reclose diaphragm valves 45 so that the compressed airwithin the tank may not be exhausted.

This is accomplished by the series of interconnected switches 22'!actuated by the piston rod I2! of the contact 3|. Accordingly, followingcircuit interruption due to a disturbance within the control linecontaining the switches 23!, and 32!, 322 and 323, contact 3! and itsassociated piston rod I2! will be displaced to the left as viewed inFigure 12 and the arc extinguished. Upon the completion of thedisplacement of all the pistons, contacts 22! will close and reenergizethe electromagnetic device 3!5 although one of the switches in theparallel control line may be open. This reenergization will result inthe closure of diaphragm valves 46.

Manual closing of the circuit breaker is accomplished by the operationof the normally open switch 35!. This switch through the agency of relay35'! controls the solenoid 330 of the air valve 332 in the closingmanifold. The energization of electromagnetic device 335 will, aspreviously mentioned, permit the influx of high pressure air throughvalve 332 to the closing cylinders and their associated pistons whichwill move the contacts 3! and 32 into engagement.

A second switch 352 with normally closed con: tacts, is in series withswitch 35!, and opens when the air pressure in tank is below a safevalue for closing the breaker on a fault. As will be seen, the cycle ofevents required for manual closing will be impossible when the contactsof switch 352 are open.

The relay 351 comprises an armature 358 normally biased to a midposition between two magnet poles (not shown) which are energized by thecoils 353 and 354. The contacts and 353 are normally open and moved tclosed position by the armature when it moves upward, toward the magnetpole of coil 354.

The coil 354 is magnetically stronger than coil 353 so that when thecoils are energized simultaneously by the closure of switch 35!, theupper coil predominates and the contacts close. The contact 35! shortcircuits the switch 35!, so that after operation it may be releasedwithout deenergizing the relay. The contact 353 completes the circuit tothe solenoid 330 of the solenoid of the closing valve. I

The circuit of coil 353, when the relay is energized, is from thenegative control bus. through coil 353 to the positive control bus. Thecircuit of the coil 354 is from the common terminal of coils 353 and354, through the coil. through contact 355 of auxiliary relay 3l5provided that relay 3l5 is energized, to the positive bus. Re-

lay coil 3I5 as hereinabove described, is energized whenever theelectromagnetic device 3!5 is energized through either of the parallelcircuits previously described.

The relay armature 353 has two different actions at deenergizationdepending upon the position of switch 35!. Thus, if switch 35! is open,the separation of contacts 355 deenergizes coil 354 and permits thecontacts 35! and 363 to part, deenergizing coil 353 and allowing thearmature to return to its normal mid-position. If the switch 35! is heldin the closed position and the contacts 355 separate, the coil 354 isdeenergized, but the coil 353 remains in circuit. The relay armature 353is therefore drawn down beyond its normal mid-position against themagnetic pole of coil 353 and held in that position with contacts 35!and 353 open. If, during this \condition, the contacts 355 of relay 3l5reclose, the contacts 35! and 353 will remain open despite thereenergization of coil 354. When the switch 35! is released, the coil353 will be deenergized and the armature will return to its normalmid-position.

The relay 3!5 provides an interlock between the tripping system and thesolenoid 33!! controlling the air pressure in the closing manifold. Whenthe breaker is tripped, the closing manifold must be disconnected fromthe storage tank and vented to the atmosphere to prevent reclosure ofthe breaker contacts when the blast valve diaphragms close.

The coil of this interlock relay 3H5 is, therefore, connected in serieswith the coil 3!5 of the tripping manifold valve 3!2 so that they aredeenergized simultaneously upon the automatic opening of any breakerpole. This action vents the trip manifold 255 for actuation of all theunoperated blast valve diaphragms, and at the same time, by theseparation of contacts 355 deenergizes relay 351.

Thus, the solenoid 335 is deenergized and the pressure in the closingmanifold is reduced to that of the atmosphere, assuring that the springsI54 will hold the breaker contacts open.

Upon the opening of all the circuit breaker poles, a control circuitwill be established throu h I the switches 22'! to reenergize coil 3!5and close all the blast valves, which as previously described, 1,

will preclude the exhaustion of the storage tank. This action willsimultaneously energize relay 3l6 and close contacts 355. Under thiscondition, as previously described, the relay 35! carmot reclose itscontacts 35! and 363, no matter whether the control switch 35! is openor closed. This effectively prevents repeated opening and closing of thebreaker contacts when the switch 35! is closed during a fault condition.

As the control system requires that full air pressure be maintained onthe closing manifold when th breaker contacts are in closed position,the coils 353 and 354 of relay 35'! and coil 330 of the air valve aredesigned for continuous duty. This condition is also true of thetripping system as the coils 3!5 and 3l5 are deenergized only duringopening movement of the breaker contacts;

It is frequently possible and desirable in the operation ofcertain'polyphase circuits, to permit 9 the switches m and m,in'parallel and through tioning the lever single pole of the circuitbreaker without necessarily interrupting the other poles there of. Moreparticularly, it has been found that internal rectifier faults such asbackflres may be cleared by merely opening and reclosing the affectedanode circuit, while permitting normal operation of the unaflectedanodes.

In order to provide for such an arrangement within the control systemillustrated in Figure 12, it is necessary to preclude the operation ofone of the switches 231 immediately upon the occurrence of an overload.Yet it is necessary to-actu ate switch 231 to interrupt all of the polesif; the anode fault is permanent in that it cannot be removed unless themercury arc rectifier is shut down and repaired.

Figur 14 illustrates one modification of a device which may be mountedupon the circuit breaker illustrated, which functionsto permit a singlepole to open and reclose several times before the entire mercury arcrectifier is taken out of operation- In order to modify the circuitbreaker in ac- -cordance with Figure 14, it is necessary to remove eachof the switches 231 from its fixed relation with shaft 111, whichcarries the armature 116 of the electromagnet 112.

Attached to the end of the shaft 111 in place of the switch 231, is apawl 311 biased by means of spring 312 into engagementwith a ratchet313. In addition, the locking device 314 is biased into cooperation withratchet 313 by means of spring 315 which may be pinned to the frame ofthe circuit breaker. r I

The occurrence of an overload will displace shaft 111 to the left asviewed in Figure 14 and V in conjunction with the pawl 311 and thelocking device 315 will rotate the ratchet 313 through A lever 313 whichis fastened to the ratchetby means of the screw 311 is positioned tooperate a switch 331 which occupies the same position as switch 231 inthe control circuit of Figure '12. Therefore, a number of operations ofshaft 111 due to repeated circuit overloads will continuously rotateratchet 313 until lever arm 316 opens switch 331'to open circuit all ofthe circuit breaker poles in a manner described in connection with theoperation of switch 231.

. A single overload occurring in one of thepoles' will move the ratchetone notch, vent the dome behind th diaphragm to open the single breaker,and due to the biasing action of the springs about shaft 111, thecircuit breaker pole in which the,

fault occurred will reclose immediately following circuit interruption.

The number ofsuccessi-ve interruptions which 'may be allowed'before allof the poles are interrupted may be predetermined by suitably posiarm313. The system as indicated in Figure 14, provides a number of cyclesprior to the interruption of the entire mercury arc rectifiers anodecircuits angle as determined by a single notch thereon.

and is cumulative in its operation, that is, l! severa1 cycles ofopening and immediate reclosing' In the above device, subsequent to theinterruption of all of the circuit breaker poles, it is necessaryto'readjust or reorient the ratchet 313 in order to reset lever 313 toits original position. In order to overcome this inconvenience, themodification illustrated in Figure 13 may be employed. In thismodification, each of the switches 231 are in circuit with a solenoid332 through a parallel circuit of an annunciator'333 and an.electrically operated counter 334.

In this modification, the switches 231 have been removed from thecontrol circuit in series with the trippin solenoid 313 and have allbeen replaced by a single switch 331 which is in operative relation withthe solenoid plunger 335, through a notching mechanism as will now beexplained. I J

This series circuit is connected across the terminals of a directcurrent control circuit such as the battery 314 of Figurel2, and thusfollowing the actuation of any of the switches-231, the solenoid plunger335 will operate upwardly as viewed in Figure 13.

The closure of one of the switches 231 will actuate the lever 333 of theannunciator about its pivot 331 to release the hog or'other resettablevisual indication 333 which provides an indication of the circuitbreaker pole which has beenoperated. This visual indicator may-be of thetype which can only be reset manually. The operation of one of theswitches 31 will correspondingly operate the associated-counter 384 toprovide some indication of the number of faults which occur in theparticular anode circuit.

The closure of any switch 231 will operate the plunger 333 upwards asviewed in Figure 13 which will in turn cause rotation of lever 332 abouta shaft 333. Rotatabl'y mounted upon the shaft 333 is a ratchet wheel334 which carries lever arm 333 in fixed relation thereto. A pawl 333which is pivotally mounted upon the lever arm 332 isbiased into enagement with the notches of ratchet 334 by means of a spring 333 andthus rotation of lever arm 332 due to axial displacements of-plunger 333will cause rotation of the ratchet 333.

A biasing spring 391 tends to rotate ratchet 333 in a direction oppositeto that obtained by an'upward displacement of plunger 33 5, and normallypulls lever 333 against a fixed stop 333.

t A locking device 431 pivotally mounted upon the pin 432 is biased inthe direction required for engagement with ratchet 334 and when inengagement therewith will prevent spring 331 from rotating the ratchet.431 is normally disengaged from ratchet 334 by means of thegravitational effect ofa piston43 332 is deenergized and thus thelocking device piston and ratchet assume the positions indicated inFigure l3,wherein it may be seen that the pawl 333 engages a stop 433which causes disengagement from ratchet wheel 334 and permits spring331'to rotate the lever 333 against its stop Energization of coil 332due to the closure of one of the switches 231 will rapidly raise plunger333 and thus rotate ratchet334 through one or more notches. In addition,the operation of However, locking device p un er rod 808 will drivepiston 4|! up into the cylinder"! and thus allow locking device 4" tocome into engagement with ratchet 384 to preclude restoration to itsoriginal position immeof the present application, between the tank andthe closed and claimed.

It will be evident that modifications of diately upon the deenergizatlonof coil "2. 5 the above-described circuit breaker design and Therefore,member 395 will remain in a substancircuit breaker control systems maybe made by tially fixed position until piston 403 and its assothoseskilled in the art and therefore I do not ciated piston rod 404 descendand disengage the wish to be limited to the specific disclosuresherelocking device 401 from the ratchet 304. inabove set forth but onlyby the scope of the The adjustable small exhaust 406 provides inappended claims. I effect, when combined with the cylinder and pis- Iclaim: ton a time delay mechanism inasmuch as the 1. In an electriccircuit interrupter for condescent of piston 403 will be relativelyslow. As trolling an electric circuit, a stationary contact the circuitbreaker operation is similar to that and a movable contact engageabletherewith, a previously described, the anode pole which has rod havingtwo pistons attached thereto of difbeen opened due to a fault willimmediately referent effectivev area, said movable contact being close.If the fault is still present within the cirsupported thereon, .a sourceof compressed air, L cuit, the switch 231 will be reclosed immediatelymeans responsive to electrical conditions of said and will again actuateplunger rod 385 to'again circuit for controlling and directing air fromrotate ratchet 384 through one or more notches. Said o e against Saidfln a t and one of said And inasmuch as piston 403 has not completedpistons having a larger effective area, for simulits descent, thelocking device 40! will again pretaneously disengaging said contacts andquenchclude the return of the ratchet to its original posiing arcs drawntherebetween; means for directtion. I ing air to the other of saidpistons for causing Therefore, it may be seen that repeated oper- 5 theengagement of said contacts; and means reations of the circuit breakercontacts will cause sponsive to the disengagemett of said coatacts for acontinued rotation of ratchet 394 and at the disconnecting said sourcfrom both said pistons. termination of the predetermined number of cy-2. In a fluid blast circuit breaker, a housing, a cles, the member 395will open switch I which, first cylinder within said housing and acorreas previously mentioned, is in the control circuit sponding pistonoperable therein, a movable conand will interrupt all of the circuitbreaker poles. tact fixed relative to said piston and engageable If, on'the other hand, a rectifier fault occurs with a stationary contact, apassage encircling and a single opening and reclosure is suilicient saidmovable contact and communicating with to clear this fault, then thedelayed descent of the face of said piston, a contact closing cylinder.-piston 403 would ultimately disengage the lock- 5 coaxial with and ofsmaller diameter than said ing device 4M from the ratchet 394 and permitfirst cylinder, 2. piston in said closing cylinder, 1 its return to itslimiting position when the coil a piston rod interconnecting saidpistons and said 382 is in the deenergized position. movable contact,means for introducing a 'fiuid If the circuit breaker is operating upona per- ,under pressure into said passage and, spirally manent rectifierfault, a succession of operations 40 about said contacts for developinga force on said will be required before switch 39l is opened to firstmentioned piston, and means for introducisolate the rectifier from thetransformer seconing a fluid under pressure into said closing cyldariinder for developing a force on said closing pis-/ Subsequent tothe'interruption, the piston 403 ton, said forces being opposed, andresilient will descend and free the ratchet from the lockmeans -forbiasing said movable contact away ing device to permit spring 391 toreturn the from said stationary contact. ratchet to its originalposition. I 3. In an electric circuit interrupter, a. station- Theentire system, as illustrated in Figure 13, my contact and a movablecontact engageable will therefore serve as a counting mechanism intherewith, said movable contact being supported order that any ,of theanodes be allowed'to opupon a rod having two pistons attached thereto,crate several times before the mercury arc reca source of compressedair, and mechanism for tifier is isolated from the line. In'addition,itcontrolling the flow of air from said source to serves to visuallyindicate upon which anode the said contacts and one of said pistons forsimulfault has occurred and thetotal numberof optaneously disengagingsaid contacts and quencherations of each pole of the circuit breaker.ing arcs drawn therebetween and means for si- It is important to notethat the-systems illusmultaneously directing air to the other of saidtrated in Figures 12, 13 and 14 are entirely sche-. pistons tending :tocause the engagement of said matic, that the valves, solenoids, relays,time decontacts. lay mechanisms and the like have been illus- 4. In anair blast circuit breaker, a housing, a, trated in their simplest {ormmerely to facilitate 6o first cylinder within said housing and acorrethe explanation of, thesystem involved. sponding piston operabletherein, a movable con- The various relays and other devices requiredtact fixed relative, to said piston and engageable may be of the knowncommercial types and need with a hollow stationary contact, an airpassage only function as the devices illustrated in order encirclingsaid movable contact and communicatthat they may be applied to thecontrol circuits. as ing with the face of said piston, a second cyl- Theclaims of the present application are diinder in said housing coaxialwith said first menrected to the structure of the circuit breaker. Inti'oned cylinder and axially displaced therefrom divisional applicationSerial No. 432,774, filed by the width-of said passage, a flangedinsulating February 28, 1942, a system in which this breaktube in saidsecond cylinder, said stationary coner may be employed,'is disclosed andclaimed. In tact being removably secured within said insulatapplicationSerial No. 516,917, filed January 4, ing tube, the inner diameter ofsaid tubebeing 1944, which isalso a division, a valve structure greaterthan the outer diameter of said piston.

for particular use with this circuit breaker, is disclosed and claimed.In application Serial No.

, 516,918, filed January 4, 1944, which is a division 5. In an air blastcircuit breaker, a housing, first cylinder within said housing and a cospending piston operable therein.

a movable n tact fixed relative to air compressed air and with saidfirst passage across operable by said said piston and ensageable with ahollow stationary contact, an air passage encirclingsaid mo le contactand'communieating with the face of said piston, a second cylinder insaid housing coaxial with said first mentioned cylinder and axiallydisplaced therefrom by the width of said passage, a flanged insulatingtube in said second cylinder, said stationary contact being removablysecured within said insulating tube, the inner diameter of said tubebeing greater than the outer diameter of said piston, a contact closingcylinder coaxial with and of smaller diameter than said first and secondcylinders, a piston in. said closing cylinder, a piston rodinterconnecting said pistons and said movable contact, means forintroducing air under pressure into said passage for developing a forceon said first mentioned piston, and means for introducing air underpressure into said closing cylinder for developing a force on saidclosing piston, said forces being opposed.

6. ,In an air blast circuit interrupterior an electric circuit, ahousing enclosing a pair of cooperable contacts, a source of compressedair, a main valve having a circular valve seat,' and an air passagesurrounding said contacts, a second passage communicating with saidsource of said circular valve seat, a valve disc for engaging said seatto prevent flow between said passages, a flexible diaphragm secured tosaid housing and supporting said valve disc, said diaphragm beingmovable toward and away from said seat, a member secured to said housingand enclosing the face of the diaphragm opposite said disc to form aspace, means responsive to conditions in said circuit for controllingthe pressure withinsaid space for governing the engagement anddisengagement of said valve disc and valve seat, comprising a duct fromsaid-compressed air supply entering into'said dome shaped space topermit the development of supply pressuretherein, means including saidlast mentioned means to vent said duct and release said pressure, asec.- ond discharge duct entering into said space from the. atmosphere,a valve for sealing said duct, said circuit responsive means including amagnet'energized in accordance with the current flowing through 'saidcontacts, said valve being currents in excess of a predetermined value,said diaphragm being operable upon the reduction of pressure in saidspace to permit the influx or air to said firstpassage to cause theseparation of said contacts.

7. In a pneumatically operated circuit interrupterfor controlling anelectric current, a stationary contact, .a large opening pistonassociated with said movable contact and a relatively small closingpiston associated with said movable contact, cylinders for said pistons,to said closing piston'for closing said contacts and maintaining them incurrent carrying engagement, means responsive to conditions in saidcircuit for applying an air pressure to said opening piston to overcomethe force on said closing pistons and opening said contacts and meansoperative onthe opening 'of said contacts for disconnecting said aircylinder. r I

8; In a pneumatically operated circuit breaker,

- a reciprocable element actuable by the difi'erence' supply from saidopening magnettovent said space for a movable contact, a relativelymeans for app yingair pressure I phere,

in pressure in opposite sides thereof, an enclosure for one side of saidelement, a source of compressed air, a first duct between said sourceand said enclosure, a first valve means for connecting said duct to saidsource or to the atmosa second valve means for opening said enclosure tothe atmosphere, a second duct between said first duct and saidenclosure, 9. check valve in said second duct for preventing flow of airfrom said first duct through said second duct to said enclosure, controlmeans for first actuating said second valve to vent said enclosure, theflow of air from said first duct assisting in the evacuation of saidenclosure, said control means subsequently efiective to vent said firstduct to the atmosphere to permit flow of air from said enclosure throughsaid .check valve to said first duct.

9. In a fluid blast circuit breaker, a housing, a first cylinder withinsaid housing and a corresponding piston operable therein, a movablecontact fixed relative to said piston and engageable witha hollowstationary contact, a passage encircling said movable contact andcommunicating with the face of 'said piston, an insulating tubing forcarrying said fixed contact, said stationary contact being removablysecured to said tubing, said contact having an additional air spacingbetween itself and said insulating tubing.

-10. In a fluid blast circuit breaker having a pair of relativelymovable contacts adapted to i engage and disengage each other, a sourceof ond' valve being connected in said second conduit.

- saidsecond valve compressed fluid, a conduit from said source of fluidto said movable contacts, a main diaphragm valve for controlling theflow of air to said conduits through said movable contacts; a secondvalve, 9. second conduit from said source oi compressed fluid to saidfirst diaphragm; said secable contact for operating said contacts .into

disengagement; .and a third conduit from said source of compressed fluids: simultaneously applying pressure from said source to said relativelymovable contacts for operating into, and maintaining said contacts inengagement, said fluid passing over said first mentioned conduitovercoming the action of said fluid in said third passage formaintaining said contacts in disengagement against the action of saidfluid in said third conduit.

ll. In a circuit breaker having a fixed and a movable contact forcontrolling an electric circuit, fluid means for operating said movablecontact into engagement with said fixed contact, and fluid meansresponsive to circuit bonditions or said electric circuit for operatingsaid movable contact to disengage said fixed contact against the actionor said contact engaging means, said contact engaging means beingoperative on the opening of said circuit for re-operating said movablecontact into engagement with means whereby said consaid'fixed contact,and v tact engaging means is rendered inefl'ective after a predeterminednumberof contact engaging operations.

' WILLIAM M. SCO'I'I. Jr;

